Electrical condenser



June 19, 1934. J, A, PROCTOR 1,963,559

ELECTRICAL CONDENSER Filed Nov. 12, 1927 '3 Sheets-Sheet l INVENTORZ Jfi j eri 93-05501 TTORNEY June 19, 1934. J PROCTOR 1,963,559

ELECTRICAL CONDENSER Filed Nov. 12, 1927 5 Sheets-Sheet 2 INVENTOR:

' ATTORNEY Jupe 19, 1934. J A, PROCTOR 1,963,559

ELECTRICAL CONDENSER Filed Nov. 12, 1927 3 Sheets-Sheet 5 as m PatentedJune 19, 1934-,

PATENT OFFICE 1,963,559 ELECTRICAL CONDENSER' John Albert Proctor,Lexington, assignor,

by mesneassignments, to General Electric Comn nyra. corporation of NewYork Application November 12,1927, Serial No. 232,742 16 Claims. (c1.175-41) This invention relates to electrical condensers and, more.particularly, to high power air condensers suitable for 'use inhighfrequency circuits such as those involvedin-radio transmissionapparatus.

High frequency electrical currents travel only over the surface of aconductor without passing any appreciable distance into the interiorthereof. Furthermore, field concentrations occur at all sharp corners-or sudden changesin current direction which may become suflicientlystrong to produce a'corona discharge. It is desirable therefore in highfrequency electrical apparatus to provide a large surface area and toavoid, as far as possible, sharp corners and projections.

\ In an air condenser for use with high power transmitters it isnecessary to provide a substantial amount of space between adjacentplates in orderto prevent a breakdown of the dielectric.

This, of course, reduces the capacity and necessitates the use of plateshaving a large area in orderto build up the desired amount of capacity.Furthermore, the plates of the two polarities must becarefully'insulated and the entire design carried out with a view topreventing excessive losses as, for example, those due to resistance andfield concentrations.

This'invention provides a high power air condenser for use-in radiotransmission circuits or other high frequency systems in which a sub-'st'antial area of plates is provided and in which the space betweenplates is maintained sufliciently great to prevent dielectric failure.are formed of a substantial thickness and are provided with roundededges. Furthermore, since only surface currents are involved, the platesare formed hollow in the interest of economy and lightness. A simplifiedmounting is em- 0 ployed for spacing the plates and suitably insulatingthe plates of different polarities.

The invention also consists in certain new and original features ofconstruction and combinations of parts hereinafter set forth andclaimed.

7 Although the novel features which are believed to be characteristic ofthis invention will be particularly pointed out in the claims appended.hereto, the invention itself, as to its objects and advantages, themode of its operation and the BO-manner of its organization may bebetter understood by referringto the following description taken inconnection with the accompanying drawings forming a part thereof, inwhich Fig. 1 is a side elevation of a condenser constructed inaccordance with this invention;

' liability of. corona discharge. The plates Fig. 2 is avplan viewthereof;

Fig. 3 is a vertical section broken away intermediate the ends of thecondenser, to avoid repetition; taken on the line 3-3 of *Fig. 2; and

Fig. 4 is a detail view of a modified form of insulator which may beused with this condenser.

Like reference characters denote like parts in the several figures ofthe drawings.

In the following description and in the claims parts will beidentifiedby specific names.for

convenience, but they are intended to be as generic in their applicationto similar parts as the art will permit.

Referring to the figures more in detail, theinvention is shownby way ofillustration as applied to a condenser comprising a plurality of plates11 which are mechanically and electrically connected together to formone condenser electrode, and a plurality of plates 12 forming a secondelectrode similarly joined together but insulated from the firstmentioned group. Each of said plates 11 and 12 is cast or otherwiseformed in two sections 13 and 14 (Fig. 3) and may be cup-shaped withrounded edges whereby, when joined together, a continuous outer surfaceis produced. The plates maybe formed ofaluminum although the inventionis not limited to the use of that particular material. The co-operatingedges of the various plates are suitably finished to fit tightlytogether and thereby reduce the resistance losses of the condenser aswell as the v Without further extended description, those skilled in thearts will understandhow to make this construction, so

as (1) to reduce the weight sustained by lower insulator 31, (2) providea strong mechanical construction of the parts notwithstanding theirreduced weight, for the plates of large facing areas, .(3) and providethe above electrically useful structure by bringing together tightly therims of the cup-sections so as to produce such external rounded edgesfor the thick hollow condenser plates. Said rounded external edges beingformed by bringing together the rims of the cups so that the two shortsides of the facing cups constitute the rounded edges of the two-cupplates.

Sections 13 and 14 may be provided with aligned openings 15 throughwhich supporting members may be passed and with suitable recesses 16afor spacing and separating the plates from parts of opposite'polarity.The sections may be joined together as by tubular'rivet 16 which servesto rigidly secure the sections together in good contact and receive asupporting member as tubes 21 or 36 as hereinafter set forth. Any othersuitable means may however be employed for joining said plate sectionsand securing electrical contact therebetween. Although the edges of theplates are rounded wherever useful yet a fiat surface 17 is providedadjacent rivets 16 for co-operating with the adjacent spacing tube 21 or36 and assuring a tight fit therewith. Surface 17 is essentially a bossformed on the surface of the plate and is utilized only for the purposeof securing proper mechanical co-operation' between the various parts.

One set of plates 11 may be supported upon rods 20 passing throughaligned rivets 16 therein. Spacing members, as metallic tubes 21, aresupported by posts 20 and serve to properly space the various plates andto electrically connect the same. Spiders 22 may be utilized for joiningthe various rods 20, being provided as shown in Figs. 2 and 3 at top andbottom and, with three legs 23 extending at equal angles therefrom. Legs23 are provided with bosses 24 which are drilled to pass over said posts20. The ends of posts 20 may be threaded and the assembly secured bynuts 25 and lock washers 26. One end of rods 20 may be utilized as aterminal to which a conductor may be secured as by nuts 27 and lock nuts28.

Spiders 22 are provided with a circular recess adapted to receive theend 30 of insulator 31. A gasket 32 of yielding material may be locatedin said recess and adapted to bear against the insulator 31 forpreventing injury thereto. Said insulator may be of a size dependentupon the I voltage which is to be employed and may be formed of anysuitable insulatingmaterial such, as porcelain or pyrex glass.

If formed of porcelain the surface of the insulator is corrugated asshown in Figs. 1 and 3 for increasing the surface distance between thetwo ends thereof. If formed of glass, however, as shown in Fig. 4 theinsulator may be tubular with a flat cylindrical surface. In this case,a slightly greater length is required in order to prevent surfacebreakdown.

Condenser plates 12 are formed in the same manner as plates 11, abovereferred to, and'are similarly mounted upon rods 35 andseparated byspacing tubes 36 around the rods. Spiders 37 are similar to spiders 22above described and may be utilized for joining the various rods 35 forelectrically and mechanically connecting the set of plates 12. Theentire assembly may be secured by nuts 38 and lock nuts 39 threaded uponthe ends of rods 35 and co-operating with threelegged spiders 37.

Spiders 3'7 are suitably recessed for receiving the end 40 of insulators31 between which the entire set of plates 12 is supported. Gasket 41 ofyieldable material such as lead may be inserted'between the ends 40 ofinsulators 31 and the respective spiders.

As shown in Figs. 1 and 3, each set of metallic condenser plates 11, 12is spider-shaped, with three wide legs, in cooperation with the twothreelegged end-supporting spiders 22, 23; the wide spider-legs ofcondenser plates 11 being staggered or offset circumferentially relativeto the legs of condenser plates 12. As shown, the pair of top and bottomthree-legged metallic end supporting spiders 22 for the set of condenserplates 11 have their legs staggered or offset circumferentially,relative to the legs of a pair of metallic end supporting spiders 3'7,and relative to the spiderlegs of condenser plates 12; and the pair ofmetallic end supporting spiders 37 for the set of 9011- denser plates 12have their legs staggered or offset circumferentially relative to thespider-legs of condenser plates '11. Thus, on the basis of the two pairsof end spiders 22 and 37 having their desirable mechanically symmetricalthree-legged construction for balanced securing of the condenser plates11 and 12 in proper electrical relations, each of all said condenserplates is formed with three recesses 16a Fig. 2, between their legs,said recesses being spaced from one another circumferentially and themetal tubes 21 and 36 respectively are spaced amply from condenserplates of high potential difference; while the spider legs of thecondenser plates, extending between the recesses 16a of the plates,provide maximum cooperating condenser surfaces within the over-alllimits of the supporting rods 20 and 36 under the desirable condition ofend-supporting spiders having at least three legs constituting the abovemechanically symmetrical and balanced construction; said maximum facingsurface areas of the cooperating condenser plates being provided by thefact that the legs of the condenser plate spiders are substantiallytwice as wide circumferentially as the plate-recesses 16a between them,while said recesses, individually of sufficient circumferential width toprovide ample electrical clearance between supporting rods 20 and 36,yet the recesses occupy no more than one-third of the total perifery, sothat twothirds is filled by useful cooperating condenser surfaces incombination with the useful threelegged construction of the endsupporting spiders.

The entire assembly may be supported upon the floor or may be insulatedtherefrom as by placing insulators (not shown) under the lower ends ofposts 20. It may be noted that the entire assembly is directly supportedby these posts since one set of plates 11 is clamped directly theretoand a second set of plates 12' is'supported from insulators 31 which aresecured by spiders 22 joining said rods 20.

In the condenser above described a suitable amount of spacing may beprovided for preventing dielectric breaking down while a sufficientarea. of plates is obtained to produce the required capacity. Asimplified supporting means whereby one set of plates is directlysupported from a pair of insulators reduces the number of points inmechanical contact between the two sets of elements. The plates may becomparatively light since they are hollow and may be readily and cheaplycast in two sections as disclosed in Fig. 3. It is essential, however,to insure a tight mechanical fit between the two sections, which may beeffected by machining the parts if necessary. Furthermore, the varioussurfaces have rounded contours whereby sharp corners are largelyeliminated.

As a specific example of a condenser which may be employed in highfrequency circuits, a spacing of one half inch between plates has beenfound satisfactory in a condenser operated on 20,000 volts and capableof passing amperes at a frequency of 1,000,000 cycles corresponding to a300 meter wave length. These figures are however, given as a matter ofillustration only The high KVA rating. is due principally to the lowloss resulting from the above described construction.

While certain novel features of the inventionhave been shown anddescribed and are pointed out in the annexed claims, it will beunderstood that various omissions, substitutions and changes in theforms and details of the device illustrated 1 said supporting posts atportions of the plates radially inward of the rounded periferies ofthe 1. A two piece condenserlplate provided withedge indentations, alledges of the'plate including said indentations being rounded and saidplate being split substantially mid-way in the plane thereof andprovided with perforations to receive supporting rods extending throughsaid plate and means between the outer surfaces of said plate forsecuring the two portions of the plate together.

2. A two piece condenser plate provided with edge indentations, alledges of the plate including said indentations being rounded and saidplate being split substantially mid-way in the plane thereof andprovided with perforations to receive supporting rods extending throughsaid plate and means between the outer surfaces of said plate forsecuring the two portions of the plate together, said securing meanscomprising tubular rivets within said perforations and thru which saidsupporting rods may pass.

\ 3. A high voltage air condenser which includes two sets of interleavedhollow spider-shaped condenser plates having at least three relativelystaggered hollow legs; two parallel metallic spider-shapedend-supporting spiders one above 30' the other for said respective setsof condenser plates and sustaining the weight thereof, both saidend-supporting spiders having their legs staggered relative to oneanother, the legs of each supporting spider being staggered relative toone of the respective sets of condenser ,plates; said hollow condenserplates having rounded edges at the sides and periferies of their legs byvirtue of their construction including -two facing cup-shaped membersjoined at the cuprims of which cups the short sides meeting at thecup-rims constitute a continuous rounded external perifery of the hollowcondenserplate, the bottoms of 3 said facing cups being formed with,registering bosses; two sets of metallic plate-supporting posts of\whicheach set extends thru the bosses of one set-of condenser plates andbetween the wide legs of the other set of condenser plates and issupported by one of said metallic end-supporting spiders; said condenserplates being connected at their bosses to plates; and a support ofcompression resisting insulating material between the upper and lowermetallic end-supporting spiders taking the weight of the upper spiderand the set of condenser plates and supporting posts carried therebyand' transferring said weight to the lower end supporting spider.

4. A high voltage air condenser which includes two sets of interleavedmetallic'plates widely spaced apart to prevent electrical break-down butof large facing areas for high capacity; a

, pair of parallel metallic supporting members one above the other andboth below said plate-sets, parallel thereto and yet more widely spacedapart than said interleaved plates; 9. set of metallic supporting posts'carried by said uppen metallic supporting member and themselvescarrying one of the sets of interleaved condenser plates; a support ofcompression-resisting insulating. material carried by the lower of saidtwo metallic supporting members and extending across said wide spacebetween the two and sustaining the weight of said upper end-supportingmember, of the posts and condenser plates supported thereby; meansproviding the necessary mechanical strength and light weight of saidparts sustained by said insulating support, and providing for reductionof resistance losses and corona discharge, said means including a hollowconstruction of the condenser plates including two cup-shaped sectionsof which the rims adjoin one another, and are closely fitted together,the short cup-sides meeting at their ,rims and constituting .acontinuous rounded external pc- 'rifery of the hollow condenser plate;and a which extend the respective sets of supporting 7 posts at portionsof the plates radiallyinward of their rounded periferies. p

5. A high voltage air condenser which includes two sets of, interleavedcondenser plates widely spaced apart to prevent electrical break-downbut of large facing areas for high capacity, two pairs of metallicsupporting members of which one member of each, pair is located'abovethe condenser plates and'the other member of each pairis located belowthe condenser plates; two parallel sets of supporting posts to whichrespectively the respective sets of condenser plates andpairs of saidsupporting members are mechanically connected; the two metallicsupporting members above the condenser plates being substantially spacedapart and connected respectively to the two'sets of supporting post's;means between said two upper metallic supports insulating them from oneanotherythe two metallic supporting; members below the condenser platesbeing electrically spaced apart and connected respectively to the twosets of supporting" posts; a support of compression-resisting insulatingmaterial between said two lower metallic F supporting members, carriedby the lower of the two supporting members and itself sustaining theupper one of the two supporting members and sustaining also the weightof the supporting posts and condenser plates carried by the said uppersupporting member; and means providing the necessary mechanical strengthand desirable light weight for the large-aread condenser plates andmetallic supporting members andtposts and providing also for reductionof resistance losses and corona discharge, said means including a hollowconstruction of the plates including two cup-shaped sections of whichthe rims adjoin one another and are closely fitted together, the sidesof the facing 'cups which adjoin at the rims forming a continuousexternal rounded perifery of 14'( the hollow condenser plate reducingresistance losses and liability to corona discharge; the bottricalbreak-down and having wide periferal pore tions circurnierentiallyspacing apart at least three relatively narrow periferal recesses; a setof supporting posts for each of the two sets of plates; two parallelmetallic supports one above the other and respectively carried by saidtwo sets of posts, the upper support carrying the weight of one of saidsets of supporting posts and the set of condenser plates thereon; aninsulating support of structural compression-resisting materialsupported on the lower support and sustaining the upper support andsustaining the posts and condenser plates supported thereby; the upperof said two metallic supports being of spider-formation for weightreduction, the ends of the legs of said spider being connected to one ofsaid sets of supporting posts; and means further reducing the load ofsaid set of large-aread condenser plates on said insulating support andproviding a mechanically strong structure for such large-aread plates,said means including a hollow construction of the plates including twocup-shaped sections of which the rims adjoin and are closely fittedtogether reducing resistance losses and liability of corona discharge,and the short sides of said cups meeting at the cup-rims forming acontinuous rounded external perifery of the condenser plate constitutinga mechanically strong and thick but hollow light weight plate and saidrounded perifery also reducing liability to corona discharge; thebottoms of the plate-cups being formed with registering apertures thruwhich said supporting posts extend at portions of the plates radiallyinward of the rounded periferies of the plates.

7. A high voltage air condenser which includes a set of at least threemetallic supporting posts taking on their lower portions the entireweight of the complete condenser, a. metallic supporting spider havingat least three legs supported at their outer portions by the lowerportions of said posts in symmetrical balanced relation; and two sets 3of condenser plates respectively supported by said sets of posts andsupporting spider in interleaved spaced plate-relation and both of saidsets of plates being spaced a substantial distance above said metallicsupporting spider; the individual plates being hollow and including twocup-shaped sections of which the rims adjoin and are closely fittedtogether, the short sides of the cups meeting at their rims forming acontinuous rounded surface at the perifery of the hollow condenser platereducing resistance losses and liability to corona discharge, and saidcups being spidershaped in correspondence with said supporting spiderbut having periferally wide legs spacing apart a corresponding number ofthree or more periferal recesses; the wide legs of one of said sets ofcondenser plates being connected to said posts, the bottoms of the legsof the spider-shaped plate-cups being formed with registering openingsthru which extend said posts atportions of the plate legs radiallyinward of their said rounded periferies; a supporting structure ofcompressionresisting insulating material mounted on and carried by saidsupporting spider; a second supporting spider carried by said insulatingsupport and having at least three legs; and a second set of at leastthree supporting posts carried by said second spider; said second set ofcondenser plates being carried by said posts in spaced relations allwhereby the weight of said second set of condenser plates, posts andsecond spider is sustained by said insulating support supported on thefirst spider.

8. A high voltage air condenser which includes a set of atleast threemetallic supporting posts taking on their lower portions the entireweight of the complete condenser, a metallic support itself connected toand supported by the lower portions of said posts and supported therebyin balanced symmetrical relation; 2. set of hollow condenser plateselectrically connected together by said posts extending parallel to saidmetallic support and consisting of cup-shaped sections formed at theirbottoms with registering apertured bosses receiving said posts the rimsof said cups adjoining one another and closely fitted together, theshort sides of said cups meeting at the rims forming a continuousrounded perifery oi" the condenser plate reducing resistance losses andliability to corona discharge; said hollow condenser plates beingelectrically connected together by said posts at said plate-bossesradially inward from their rounded periferies, the plates being alsosupported by said posts and so supported in balanced symmetricalrelation; a second set of condenser plates similar to said first set andinterleaved therewith in high potential spaced relation; a second set ofat least three metallic supporting posts extending thru the aperturedregistering bosses of said second set of condenser plates andelectrically connecting them together and supporting them in balancedsymmetrical relation; a second metallic support itself connected to saidsecond set of posts in a position parallel to said first metallicsupport and taking the weight of said second set of posts and condenserplates; and a supporting connection of structural compression-resistinginsulating material be tween said two metallic supports and causing thefirst support to take the weight of .the second support and its set ofposts and condenser plates by way of compression stresses on saidsupporting insulating connection, the connection of said first metallicsupport with said first set of posts causing the lower ends of thelatter to take the weight of all the posts and condenser plates and ofboth said metallic supports, said lower post-ends proj'ecting below saidfirst metallic support.

9. A high voltage air condenser which includes two sets each of at leastthree metallic'supporting posts, two interleaved sets of hollowcondenser plates respectively electrically connected togeth er byconnection to said respective sets of posts in balanced symmetricalrelations; said hollow condenser plates consisting of two cup-shapedsections formed at the cup-bottoms with registering apertured bosses forthe reception of said supporting and connecting posts, the rims of saidcups adjoining and closely fitted together, and the short sides of thecups forming a rounded perifery of the hollow condenser plate extendingacross the adjoining rims of the cups, reducing resistance losses andliability to corona discharge; and means on the respective sets of postsfor clamping together the several sectional condenser plates carried bysaid posts, said clamping means including metallic spacing tubes aroundthe posts and between the successive sectional plate units, andincluding also threaded pressureadjusting means on the ends of theposts, said spacing tubes abutting against the apertured bosses of therespective cup-shaped sections of the condenserplate, and said threadedmeans forcing said tubes and bosses into compressing relations; saidbosses at the bottoms of the platecups and said clamping spacing tubesbearing against the bosses being located at the hollow portions of thecups at portions thereof radially inward of the rounded periferies ofthe condenser plates formed by the adjoining rims and short sides of thefacing cups.

10. A high voltage air condenser which includes a set of at least threemetallic supporting posts taking on their lower portions the entireweight of the complete condenser, a metallic support itself connected toand supported by said posts at their lower portions and supportedthereby in balanced symmetrical relation; a set of condenser plates alsoconnected by said supporting posts in spaced high potential relationsparallel to said metallic support and to one another, said plates beingelectrically connected together by said posts and also supported therebyin balanced symmetrical relations; a second set of condenser platesinterleaved with said first set; a second set of at least three metallicsupporting posts connected to said second set of condenser plates inbalanced symmetrical relation and electrically connecting said platestogether; a second metallic support itself connected to said second setof posts in a position parallel to said first metallic support, andtaking the weight of said second set of posts and condenser plates; anda supporting connection of structural insulating material between saidtwo metallic supports and causing the first support to take the weightof the second support and its set of posts and condenser plates by wayof compression stresses on said supporting insulating connection, theconnection of said first metallic support with said first set of postscausing the lower portions of the latter to take the weight of all theposts and condenser plates and of both said metallic supports, saidweight-taking lower postportions projecting below said first metallicsupport.

11. An atmospheric air condenser including two interleaved sets ofspider-shaped armature plates arranged one above the other, two pairsof; spidershaped supports for said armatures one of said pairs ofsupporting spiders being located above and the other below theinterleaved armatures; the legs of the spiders of each pair beingarranged in staggered relation to one another; the legs of the alternateinterleaved spider-armatures being arranged in staggered relation to oneanother; and the legs of the two supporting spiders which lie nearer thetop and bottom of the interleaved armatures being arranged inregistering relation with the legs of the armatures respectively nearestto; them; and the bottom pair of supporting spiders being separated by amember of compression resisting insulating material sustaining theweight of the upper spider of said bottom pair and of the alternatingarmatures of which the legs are in registery with said upper spider.

12. A hollow condenser armature which includes a pair of spider-shapedmetallic members having wide legs formed as shallow thin-bottomed cups,the tin bottoms of each of the cupped legs of each spider being formedwith a plurality of perforations, and with a corresponding plurality ofintegral annular strengthening bosses on the inside walls of the bottomsconstituting continuations of said cup-bottom-perforations; said cuppedspiders being arranged together edge to edge, their short cup-sidesmeeting at the edges and cooperatively constituting a blunt armatureperifery, and their respective bottom perforations and bosses beingformed in an arrangement for registry with one another when the cups arearranged in said edge-to-edge relation.

13. A hollow condenser armature which includes a pair of wide andshallow metallic cups, the bottom of each cup being formed with aplurality of perforations and one cup at least being formed on theinterior wall of its bottom with integral annular bosses constitutingcontinuations of the perforations thru its bottom; said cups beingarranged together edge to edge, their short sides meeting at their edgescooperatively constituting a blunt armature perifery, and theirrespective bottom perforations being formed'in an arrangement forregistry with one another, and with said annular bosses when the cupsare arranged in said edge-meeting relation.

14. A hollow condenser armature which includes a pair of spider-shapedmetallic members having wide legs of shallow cup formation, the bottomof each cup being formed with a plurality of perforations, and thespider-members being arranged edge to edge and their short sides meetingat their edges constituting a blunt armature perifery; said bottomperforations thru the spider-cups being formed in an arrangement forregistry with one another when the cups are arranged in saidedge-meeting relation.

15. A hollow condenser armature which inwhich consists of a wide-leggedmetallic spider,

the wide legs being formed as shallow thin-bottom cups, and the bottomof each cupped leg being formed with a perforation and with astrengthening boss for the thin metal bottom.

' JOHN ALBERT PROC'I'OR.

